CA1150884A - Process for producing polybutadiene rubber with enhanced mechanical strength - Google Patents
Process for producing polybutadiene rubber with enhanced mechanical strengthInfo
- Publication number
- CA1150884A CA1150884A CA000366910A CA366910A CA1150884A CA 1150884 A CA1150884 A CA 1150884A CA 000366910 A CA000366910 A CA 000366910A CA 366910 A CA366910 A CA 366910A CA 1150884 A CA1150884 A CA 1150884A
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- polymerization
- butadiene
- cis
- cobalt
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F295/00—Macromolecular compounds obtained by polymerisation using successively different catalyst types without deactivating the intermediate polymer
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F136/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
- C08F136/02—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
- C08F136/04—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
- C08F136/06—Butadiene
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
PROCESS FOR PRODUCING POLYBUTADIENE RUBBER
WITH ENHANCED MECHANICAL STRENGTH
ABSTRACT OF THE DISCLOSURE
A polybutadiene rubber having an enhanced mechanical strength is produced by a process comprising two successive steps of:
(A) cis-1,4-polymerizing 1,3-butadiene in a poly-merization medium in the presence of a catalyst comprising a cobalt compound and a dialkyl aluminium halide of the formula (I): A?R2X, wherein R = C2-8 alkyl and X = halogen, and;
(B) subjecting a mixture of the resultant cis-1,4--polybutadiene and the non-reacted 1,3-butadiene in the polymerization medium to a 1,2-polymerization in the presence of a catalyst comprising a cobalt compound, a dialkyl aluminium halide of the formula (I), carbon disulfide and an electron donative organic compound.
WITH ENHANCED MECHANICAL STRENGTH
ABSTRACT OF THE DISCLOSURE
A polybutadiene rubber having an enhanced mechanical strength is produced by a process comprising two successive steps of:
(A) cis-1,4-polymerizing 1,3-butadiene in a poly-merization medium in the presence of a catalyst comprising a cobalt compound and a dialkyl aluminium halide of the formula (I): A?R2X, wherein R = C2-8 alkyl and X = halogen, and;
(B) subjecting a mixture of the resultant cis-1,4--polybutadiene and the non-reacted 1,3-butadiene in the polymerization medium to a 1,2-polymerization in the presence of a catalyst comprising a cobalt compound, a dialkyl aluminium halide of the formula (I), carbon disulfide and an electron donative organic compound.
Description
115~8'~
PROCESS FOR PRODUCING POLYBUTADIE~E RUBBER
WITH ENHANCED ~1EC~ANICAL STRENGT~I
FIELD OF THE INVEN~ION
The present invention relates to a process for producing a polybutadiene rubber with an enhanced mechanical strength.
BACKGROUND OF THE INVE~TION
Japanese Patent Application Publication 49-17666 (1974) discloses a process for preparing a polybutadiene rubber with an enhanced mechanical strength. This process comprises two successive steps of the first polymerization in which a first polymerization mixture containing 1,3-butadiene and a polymerization medium is subjected to a polymerization in the presence of a cis-1,4-polymerization catalyst which has been prepared from a cobalt compound and a halogen-containing organic aluminium compound of the formula:
AQR X
n 3-n wherein R represents a member selected from the group consisting of alkyl radicals having 1 to 6 carbon atoms, a phenyl radical and cycloalkyl radicals, X represents a halogen atom and n represents a numeral of from 1.5 to 2, to produce cis-1,4-polybutadiene, and; the second poly-merization in which a second polymerization mixture containing the resultant first polymerization mixture and, optionally, both or either one of additional amounts of 1,3-butadiene and said polymerization medium, is subjected to a polymerization in the presence of a 1,2-polymerization catalyst which comprises (1) a cobalt compound, ~2) an organic aluminium compound of the formula:
30 wherein R is as defined above, and (3) carbon disulfide, to prepare a polybutadiene rubber.
The above-mentioned process is disadvantageous in that the organic aluminium compound to be used as a component of ,, ~
:~15()~
the cis-1,4-polymerization catalyst is different from the organic aluminium compound to be used as a component of the 1,2-polymerization catalyst. That is, it is necessary to use two different types of aluminium compounds. This necessity causes the catalyst-preparation procedure to be complicated and costly. Therefore, it is preferable if a single type of aluminium compound can be used as a component of both the cis-1,4-polymerization catalyst and the l,2-polymerization catalyst.
SU~ARY OF THE INVENTION
An object of the present invention is to provide a process for producing a polybutadiene rubber with an enhanced mechanical strength, by using a single type of aluminium compound as a component of both the cis-1,4-polymerization and 1,2-polymerization catalysts.
Other objects and advantages of the present invention will be apparent from the following description.
In accordance with the present invention, there is provided a process for producing a polybutadiene rubber with an enhanced mechanical strength, comprising two successive steps of:
(A) subjecting a first polymerization mixture comprising l,3-butadiene and a polymerization medium to a first polymerization in the presence of a cis-1,4-polymeri-zation catalyst which comprises (a) a cobalt compound soluble in said poly-merization medium, and (b) a dialkyl aluminium halide of the formula (I):
A~R2X (I) wherein R represents an alkyl radical having 2 to 8 carbon atoms and X represents a halogen atom, to convert at least a portion of the amount of said 1,3-butadiene used to cis-1,4-polybutadiene, and;
(B) subjecting a second polymerization mixture comprising the resultant cis-1,4-polybutadiene, non-reacted 1,3-butadiene and said polymerization medium, to a second polymerization in the presence of a 1,2-polymerization ~ 15~8~'~
catalyst which comprises:
(c) a cobalt compound soluble in said poly-merization ~edium, (d) a dialkyl aluminium halide of s~id formula (I), (e) carbon disulfide and, (f) an electron donative organic compound, to convert said cis-1,4-polybutadiene and said 1,3-butadiene to a polybutadiene rubber.
DETAILED DESCRIPTION OF THE INVENTION
In the first step of the process of the present invention, a first polymerization mixture comprising 1,3-butadiene and a polymerization medium is subjected to a first polymerization procedure in the presence of a cis-1,4-polymerization catalyst, to convert at least a portion of the amount of the 1,3-butadiene used to a cis-1,4-polybutadiene.
The cis-1,4-polymerization catalyst comprises the elements of:
(a) a cobalt compound soluble in the polymerization medium and, (b) a dialkyl aluminium halide of the formula (I):
AQR2X (I) wherein R represents an alkyl radical having 2 to 8 carbon atoms and X represents a halogen atom.
The cobalt compound is not limited to a specific type of cobalt compound, as long as the cobalt compound is soluble in the polymerization medium. For example, the cobalt compound may be selected from a group consisting of cobalt complexes with ~-diketones of the formula (II):
Rl ~4 - C - C - C - R (II) O R2 o wherein Rl and R2 represent an aliphatic hydrocarbon radical having 1 to 3 carbon atoms, respectively, and R3 and R4 represent at least one member selected from the group consisting of a hydrogen atom and aliphatic hydrocarbon - 115~88'~
radicals having 1 to 3 carbon atoms, respectively; cobalt complexes with ~-keto acid esters of the formula (III):
Rl R - C - C - C - O - R (III) O R2 o wherein ~1, R2, R3, and R4 are as difined in preceding for~ula (II); cobalt salts of organic carboxylic acids having 6 or more carbon atoms, and; cobalt halide complexes of the formula (IV):
CoXn-Ym (IV) wherein X represents a halogen atom as defined above, n represents an integer of 2 or 3, Y represents an organic ligand capable of forming a complex in coordination with the cobalt halide (CoXn), m represents an integer of from 1 to 4.
Preferable examples of the cobalt-~-diketone complexes are cobalt (II) acetylacetonate and cobalt (III) acetyl-acetonate. A preferable example of the cobalt-~-keto acid ester is cobalt acetacetic ethyl ester. The cobalt salts of the organic carboxylic acids are preferably selected from a group consisting of cobalt octoate, cobalt naph-thenate and cobalt benzoate.
In the cobalt halide complexes of the formula (IV), it is preferable that X represents a chlorine atom, and the organic ligand Y is selected from a group consisting of amine compounds, for example, pyridine, triethylamine, tributylamine and dimetyhlaniline; alcohol compounds, for instance methyl alcohol and ethyl alcohol and; N,N--dialkylamide compounds, for instance, N,N-dimethylformamide, N,N-di~ethylacetamide and N,N-diethylformamide. Especially, it is preferable that the cobalt halide complex be a cobalt chloride-pyridine complex or a cobalt chloride-ethylalcohol complex.
~he dialkyl aluminium halide of the formula (II) is preferably diethyl aluminium chloride.
In the ~irst polymerization procedure, it is preferable 115(~
that the cis-1,4-polymerization catalyst used contain 0.005 millimoles or more, more preferably, 0.01 millimoles or more, of the cobalt compound and O.S millimoles or more, more preferably, 1 millimole or more of the dialkyl aluminium halide, per mole of the 1,3-butadiene contained in the first polymerization mixture. Also, it is preferable that the molar ratio of the amount of the alkyl aluminium halide to the amount of the cobalt compound in the cis-1,4-polymexization catalyst is 5 : 1 or more, more preferably, 15 : 1 or more.
The polymerization medium to be contained in the first polymerization mixture can be selected from organic solvents capable of dissolving the cis-1,4-polybutadiene produced in the first polymerization procedure. The polymerzation medium may consist of at least one member selected from aromatic hydrocarbons, for example, benzene, toluene and xylene; aliphatic hydrocarbons, for example, n-heptane, and n-hexane; cycloaliphatic hydrocarbons, for example, cyclohexane, and; halogenated hydrocarbons, for example, chlorobenzene, o-dichlorobenzene, methylene chloride, 1,2-dichloroethane and 1,1,2-trichloroethane. It is preferable that the content of water in the polymerization medium be in the range of from 5 to 50 mg/Q.
The first polymerization (cis-1,4-polymerization) procedure of 1,3-butadiene is preferably carried out at a temperature of from -20 to 80C, more preferably, from 20 to 70C, under atmospheric pressure or higher, for a period of from 10 minutes to 5 hours. Also, it is preferable that the content of 1,3-butadiene in the first poly~erization mixture is in a range of from 5 to 40% based on the entire weight of the first polymerization mixture.
The first polymerization (cis-1,4-polymerization) procedure is preferably carried out so that the resultant cis-1,4-polybutadiene contains 90% or more, more preferably, 95~ or more of cis-1,4-structure and has an intrinsic viscosity of from 1 to 4, more preferably, 1.3 to 3, determined in toluene at a temperature of 30C. In order ilSt~88 ~
to adjust the intrinsic viscosity of the resultant cis-1,4--polybutadiene to a desired value, the first polymerization mixture may be admixed with a molecular weight-regulating agent, for example, a non-conjugated diene compound, for instance, cyclooctadien (COD) or allene or an -olefin compound, for example, ethylene, propylene or butene-l.
In the second step of the process of the present invention, a second polymerization mixture comprising the resultant cis-1,4-polybutadiene, non-reacted 1,3-butadiene and the polymerization medium, are subjected to a second polymerization procedure in the presence of a 1,2-poly-merization catalyst without deactivatiny the remaining cis-1,4-polymerization catalyst, to produce a polybutadiene rubber.
The second polymerization mixture may consist of the resultant first polymerization mixture alone, if it contains necessary amounts of non-reacted 1,3-butadiene and the polymerization medium. Otherwise, the second polymeri-zation mixture is prepared by adding an additional amount of non-reacted 1,3-butadiene and/or an additional amount of the polymerization medium, to the resultant first polymeri-zation mixture, so that necessary amounts of the resultant cis-1,4-polybutadiene, non-reacted 1,3-butadiene and the polymerization medium are contained in the second polymeri-zation mixture.
The second polymerization is effected in the presence of an 1,2-polymerization catalyst which comprises:
(c) a co~alt compound soluble in the poly~erization medium, (d) a dialkyl aluminium halide of the formula (I), (e) carbon disulfide and, (f) an electron donative organic compound.
The co~alt compound may be selected from the same group as that of the cobalt compounds usable for the cis--1,4-polymerization catalyst.
The dialkyl aluminium halide may be selected from the same group as that usable for the cis-1,4-polymerization :~15~ 4 catalyst.
The carbon disulfide is not limited to a specific grade. However, it is preferable that the carbon disulfide contain no water.
The electron donative organic compounds may include polyether compounds, for example, diethylene glycol dimethylether, diethylene glycol di-n-butylether and triethylene glycol dimethylether; aliphatic carboxylic esters, for example, dimethyl fumarate; aliphatic ketones, for example, acetone; aliphatic acetals, for example, acetaldehyde diethylacetal; aliphatic N,N-dialkylamides, for example, N,N-dimethyl formamide, N,N-dimethylacetamide;
aliphatic dialkylsulfoxides, for example, dimethylsulfoxide and; trialkyl phosphates, for example, trimethyl phosphate.
In the second polymerization procedure, it is preferable that the l,2-polymerization catalyst used contain from 0.005 to 0.5 millimoles of the cobalt compound, from 0.1 to 50 millimoles of the dialkyl aluminium halide, from 0.01 to 10 millimoles of the carbon disulfide and from 0.05 to 5 millimoles of the electron donative organic compound, per mole of the non-reacted 1,3-butadien~ contained in the second polymerization mixture. Also, it is preferable in the 1,2-polymerization catalyst that the molar ratio of the amount of the dialkyl aluminium halide to the amount of the cobalt compound be 5 : 1 or more, more preferably, 15 ~ 200 : 1. Furthermore, it is preferable that the electron donative organic compound be used in such an amount that the sum of the molar amounts of the electron donative organic compound and water contained in the second polymerization mixture be less than the molar amount of the dialkyl aluminium halide. Moreover, it is preferable that the content of the electron donative organic compound in the 1,2-polymerization catalyst be in the range of from 0.05 to 0.9 moles, more preferably, from 0.1 to 0.4 moles, per mole of the dialkyl aluminium halide.
The second polymerization procedure is preferably effected at a temperature of from -20 to 80C, more llS~84 preferably, from 20 to 60C, under atmospheric pressure or higher, for a period of from 10 minutes to 5 hours.
The polymerization medium to be contained in the second polymerization mixture may be the same as that in the first polymerization mixture.
In the process of the present invention, the first polymerization mixture may contain entire amounts of non-reacted 1,3-butadiene and the polymerization medium necessary for the production of the polybutadiene rubber.
In this case, after the first polymerization procedure is completed, the entire amount of the resultant first poly-merization mixture is used as a second polymerization mixture. In the other cases, the resultant first polymeri-zation mixture is admixed with an additional amount of the non-reacted 1,3-butadiene and/or the polymerization medium so as to prepare the second polymerization mixture containing the necessary amounts of the cis-1,4-polybutadiene, non--reacted 1,3-butadiene and polymerization medium. In any cases, it is preferable that the content of the non-reacted 1,3-butadiene in the second polymerization mixture be in the range of from 3 to 40% by weight.
In the industrial practice of the process of the present invention, each of the first and second polymeri-zations may be carried out in a batch-type procedure. In this case, after the first polymerization is completed, the second polymerization may be carried out in the same reaction vessel as that in which the first polymerization was conducted. Also, the first polymerization is carried out continuously and, then, the second polymerization is effected continuously by using a continuous polymerization reactor having a first polymerization zone and a successive second polymerization zone.
After the second polymerization procedure is completed, the resultant polybutadiene rubber can be isolated from the reaction mix~ure by a known method. For example, after the second polymerization reaction is completed, in order to stop the second polymerization, a large amount of a polar 115~
g solvent, for example, an alchol or water, which is reactive to the dialkyl aluminium halide is added to the reaction mixture to deactivate the 1,2-polymerization mixture. In another method, the reaction mixture is poured into a large amount of the polar solvent. In still another method, a small amount of a polar solvent containing an inorganic acid, for example, hydrochloric acid or sulfuric acid; an organic acid, for example, acetic acid or benzoic acid, or monoethanolamine or ammonia, to the resultant reaction mixture. In another method, hydrogen chloride gas is introduced into the reaction mixture. After the second polymerization is stopped, the resultant polybutadiene rubber is precipitated from the reaction mixture by adding a precipitating agent, for example, methyl alcohol or by evaporating the polymerization medium from the reaction mixture. The evaporation of the polymerization medium may be carried out by blowing steam into the reaction mixture.
The precipitated polymer is separated from the reaction mixture and, finally, dried.
In the process of the present invention, it is preferable that the amount of 1,3-butadiene cis-1,4--polymerized in the first polymerization procedure be in the range of 70 to 95% based on the entire weight of the polymerized 1,3-butadiene, and the amount of 1,3-butadiene 1,2-polymerized in the second polymerization procedure be in the range of from 5 to 30~ based on the entire weight ~f the polymerized 1,3-butadiene in this process.
The polybutadiene rubber prepared in accordance with the process of the present invention comprises a boiling 30 n-hexane-soluble fraction thereof having an intrinsic viscosity of from 1 to 5, determined in toluene at a temperature of 30C and containing 95% or more of a cis--1,4-structure and a boiling n-hexane-insoluble fraction thereof having a reduced viscosity of from 0.5 to 5, 35 determined in tetrahydronaphthalene at a temperature of 135C, and a melting point of 180C or more, and containing 85% or more of an 1,2-structure.
li5~84 In the polybutadiene rubber, it is preferable that the amount of the boiling n-hexane-soluble fraction be in the range of from 70 to 95% by weight and the amount of the boiling n-hexane-insoluble fraction be in the range of from 5 to 30% by weight.
The polybutadiene rubber obtained in accordance with the process of the present invention can be vulcanized by a known vulcanizing method, and the resultant vulcanized rubber product, for example, tire can exhibit an excellent tear strength, flex-crac~ resistance and tensile strength.
The polybutadiene rubber produced in accordance with the process of the present invention may contain conventional additives, for example, vulcanizing agent, vulcanizing accelerator, reinforcing agent, filler, antioxidant, pigment, process oil and the like, which are usually blended with natural rubber or high cis-1,4-polybutadiene rubbers.
Also, the polybutadiene rubber of the present invention may be blended with natural rubber or other synthetic rubbers.
The polybutadiene rubber produced in accordance with the present invention has not only the same advantaqe and feature as those of cis-1,4-polybutadiene, but also, has greatly enhanced tear strength and flex-crack resistance when the polybutadiene rubber is vulcanized and converted into a final product.
The present invention will be further explained in the following examples and through comparative examples. In the examples and the comparative examples, the amount of the boiling n-hexane-insoluble fraction of the resultant polybutadiene rubber was determined in such a manner that
PROCESS FOR PRODUCING POLYBUTADIE~E RUBBER
WITH ENHANCED ~1EC~ANICAL STRENGT~I
FIELD OF THE INVEN~ION
The present invention relates to a process for producing a polybutadiene rubber with an enhanced mechanical strength.
BACKGROUND OF THE INVE~TION
Japanese Patent Application Publication 49-17666 (1974) discloses a process for preparing a polybutadiene rubber with an enhanced mechanical strength. This process comprises two successive steps of the first polymerization in which a first polymerization mixture containing 1,3-butadiene and a polymerization medium is subjected to a polymerization in the presence of a cis-1,4-polymerization catalyst which has been prepared from a cobalt compound and a halogen-containing organic aluminium compound of the formula:
AQR X
n 3-n wherein R represents a member selected from the group consisting of alkyl radicals having 1 to 6 carbon atoms, a phenyl radical and cycloalkyl radicals, X represents a halogen atom and n represents a numeral of from 1.5 to 2, to produce cis-1,4-polybutadiene, and; the second poly-merization in which a second polymerization mixture containing the resultant first polymerization mixture and, optionally, both or either one of additional amounts of 1,3-butadiene and said polymerization medium, is subjected to a polymerization in the presence of a 1,2-polymerization catalyst which comprises (1) a cobalt compound, ~2) an organic aluminium compound of the formula:
30 wherein R is as defined above, and (3) carbon disulfide, to prepare a polybutadiene rubber.
The above-mentioned process is disadvantageous in that the organic aluminium compound to be used as a component of ,, ~
:~15()~
the cis-1,4-polymerization catalyst is different from the organic aluminium compound to be used as a component of the 1,2-polymerization catalyst. That is, it is necessary to use two different types of aluminium compounds. This necessity causes the catalyst-preparation procedure to be complicated and costly. Therefore, it is preferable if a single type of aluminium compound can be used as a component of both the cis-1,4-polymerization catalyst and the l,2-polymerization catalyst.
SU~ARY OF THE INVENTION
An object of the present invention is to provide a process for producing a polybutadiene rubber with an enhanced mechanical strength, by using a single type of aluminium compound as a component of both the cis-1,4-polymerization and 1,2-polymerization catalysts.
Other objects and advantages of the present invention will be apparent from the following description.
In accordance with the present invention, there is provided a process for producing a polybutadiene rubber with an enhanced mechanical strength, comprising two successive steps of:
(A) subjecting a first polymerization mixture comprising l,3-butadiene and a polymerization medium to a first polymerization in the presence of a cis-1,4-polymeri-zation catalyst which comprises (a) a cobalt compound soluble in said poly-merization medium, and (b) a dialkyl aluminium halide of the formula (I):
A~R2X (I) wherein R represents an alkyl radical having 2 to 8 carbon atoms and X represents a halogen atom, to convert at least a portion of the amount of said 1,3-butadiene used to cis-1,4-polybutadiene, and;
(B) subjecting a second polymerization mixture comprising the resultant cis-1,4-polybutadiene, non-reacted 1,3-butadiene and said polymerization medium, to a second polymerization in the presence of a 1,2-polymerization ~ 15~8~'~
catalyst which comprises:
(c) a cobalt compound soluble in said poly-merization ~edium, (d) a dialkyl aluminium halide of s~id formula (I), (e) carbon disulfide and, (f) an electron donative organic compound, to convert said cis-1,4-polybutadiene and said 1,3-butadiene to a polybutadiene rubber.
DETAILED DESCRIPTION OF THE INVENTION
In the first step of the process of the present invention, a first polymerization mixture comprising 1,3-butadiene and a polymerization medium is subjected to a first polymerization procedure in the presence of a cis-1,4-polymerization catalyst, to convert at least a portion of the amount of the 1,3-butadiene used to a cis-1,4-polybutadiene.
The cis-1,4-polymerization catalyst comprises the elements of:
(a) a cobalt compound soluble in the polymerization medium and, (b) a dialkyl aluminium halide of the formula (I):
AQR2X (I) wherein R represents an alkyl radical having 2 to 8 carbon atoms and X represents a halogen atom.
The cobalt compound is not limited to a specific type of cobalt compound, as long as the cobalt compound is soluble in the polymerization medium. For example, the cobalt compound may be selected from a group consisting of cobalt complexes with ~-diketones of the formula (II):
Rl ~4 - C - C - C - R (II) O R2 o wherein Rl and R2 represent an aliphatic hydrocarbon radical having 1 to 3 carbon atoms, respectively, and R3 and R4 represent at least one member selected from the group consisting of a hydrogen atom and aliphatic hydrocarbon - 115~88'~
radicals having 1 to 3 carbon atoms, respectively; cobalt complexes with ~-keto acid esters of the formula (III):
Rl R - C - C - C - O - R (III) O R2 o wherein ~1, R2, R3, and R4 are as difined in preceding for~ula (II); cobalt salts of organic carboxylic acids having 6 or more carbon atoms, and; cobalt halide complexes of the formula (IV):
CoXn-Ym (IV) wherein X represents a halogen atom as defined above, n represents an integer of 2 or 3, Y represents an organic ligand capable of forming a complex in coordination with the cobalt halide (CoXn), m represents an integer of from 1 to 4.
Preferable examples of the cobalt-~-diketone complexes are cobalt (II) acetylacetonate and cobalt (III) acetyl-acetonate. A preferable example of the cobalt-~-keto acid ester is cobalt acetacetic ethyl ester. The cobalt salts of the organic carboxylic acids are preferably selected from a group consisting of cobalt octoate, cobalt naph-thenate and cobalt benzoate.
In the cobalt halide complexes of the formula (IV), it is preferable that X represents a chlorine atom, and the organic ligand Y is selected from a group consisting of amine compounds, for example, pyridine, triethylamine, tributylamine and dimetyhlaniline; alcohol compounds, for instance methyl alcohol and ethyl alcohol and; N,N--dialkylamide compounds, for instance, N,N-dimethylformamide, N,N-di~ethylacetamide and N,N-diethylformamide. Especially, it is preferable that the cobalt halide complex be a cobalt chloride-pyridine complex or a cobalt chloride-ethylalcohol complex.
~he dialkyl aluminium halide of the formula (II) is preferably diethyl aluminium chloride.
In the ~irst polymerization procedure, it is preferable 115(~
that the cis-1,4-polymerization catalyst used contain 0.005 millimoles or more, more preferably, 0.01 millimoles or more, of the cobalt compound and O.S millimoles or more, more preferably, 1 millimole or more of the dialkyl aluminium halide, per mole of the 1,3-butadiene contained in the first polymerization mixture. Also, it is preferable that the molar ratio of the amount of the alkyl aluminium halide to the amount of the cobalt compound in the cis-1,4-polymexization catalyst is 5 : 1 or more, more preferably, 15 : 1 or more.
The polymerization medium to be contained in the first polymerization mixture can be selected from organic solvents capable of dissolving the cis-1,4-polybutadiene produced in the first polymerization procedure. The polymerzation medium may consist of at least one member selected from aromatic hydrocarbons, for example, benzene, toluene and xylene; aliphatic hydrocarbons, for example, n-heptane, and n-hexane; cycloaliphatic hydrocarbons, for example, cyclohexane, and; halogenated hydrocarbons, for example, chlorobenzene, o-dichlorobenzene, methylene chloride, 1,2-dichloroethane and 1,1,2-trichloroethane. It is preferable that the content of water in the polymerization medium be in the range of from 5 to 50 mg/Q.
The first polymerization (cis-1,4-polymerization) procedure of 1,3-butadiene is preferably carried out at a temperature of from -20 to 80C, more preferably, from 20 to 70C, under atmospheric pressure or higher, for a period of from 10 minutes to 5 hours. Also, it is preferable that the content of 1,3-butadiene in the first poly~erization mixture is in a range of from 5 to 40% based on the entire weight of the first polymerization mixture.
The first polymerization (cis-1,4-polymerization) procedure is preferably carried out so that the resultant cis-1,4-polybutadiene contains 90% or more, more preferably, 95~ or more of cis-1,4-structure and has an intrinsic viscosity of from 1 to 4, more preferably, 1.3 to 3, determined in toluene at a temperature of 30C. In order ilSt~88 ~
to adjust the intrinsic viscosity of the resultant cis-1,4--polybutadiene to a desired value, the first polymerization mixture may be admixed with a molecular weight-regulating agent, for example, a non-conjugated diene compound, for instance, cyclooctadien (COD) or allene or an -olefin compound, for example, ethylene, propylene or butene-l.
In the second step of the process of the present invention, a second polymerization mixture comprising the resultant cis-1,4-polybutadiene, non-reacted 1,3-butadiene and the polymerization medium, are subjected to a second polymerization procedure in the presence of a 1,2-poly-merization catalyst without deactivatiny the remaining cis-1,4-polymerization catalyst, to produce a polybutadiene rubber.
The second polymerization mixture may consist of the resultant first polymerization mixture alone, if it contains necessary amounts of non-reacted 1,3-butadiene and the polymerization medium. Otherwise, the second polymeri-zation mixture is prepared by adding an additional amount of non-reacted 1,3-butadiene and/or an additional amount of the polymerization medium, to the resultant first polymeri-zation mixture, so that necessary amounts of the resultant cis-1,4-polybutadiene, non-reacted 1,3-butadiene and the polymerization medium are contained in the second polymeri-zation mixture.
The second polymerization is effected in the presence of an 1,2-polymerization catalyst which comprises:
(c) a co~alt compound soluble in the poly~erization medium, (d) a dialkyl aluminium halide of the formula (I), (e) carbon disulfide and, (f) an electron donative organic compound.
The co~alt compound may be selected from the same group as that of the cobalt compounds usable for the cis--1,4-polymerization catalyst.
The dialkyl aluminium halide may be selected from the same group as that usable for the cis-1,4-polymerization :~15~ 4 catalyst.
The carbon disulfide is not limited to a specific grade. However, it is preferable that the carbon disulfide contain no water.
The electron donative organic compounds may include polyether compounds, for example, diethylene glycol dimethylether, diethylene glycol di-n-butylether and triethylene glycol dimethylether; aliphatic carboxylic esters, for example, dimethyl fumarate; aliphatic ketones, for example, acetone; aliphatic acetals, for example, acetaldehyde diethylacetal; aliphatic N,N-dialkylamides, for example, N,N-dimethyl formamide, N,N-dimethylacetamide;
aliphatic dialkylsulfoxides, for example, dimethylsulfoxide and; trialkyl phosphates, for example, trimethyl phosphate.
In the second polymerization procedure, it is preferable that the l,2-polymerization catalyst used contain from 0.005 to 0.5 millimoles of the cobalt compound, from 0.1 to 50 millimoles of the dialkyl aluminium halide, from 0.01 to 10 millimoles of the carbon disulfide and from 0.05 to 5 millimoles of the electron donative organic compound, per mole of the non-reacted 1,3-butadien~ contained in the second polymerization mixture. Also, it is preferable in the 1,2-polymerization catalyst that the molar ratio of the amount of the dialkyl aluminium halide to the amount of the cobalt compound be 5 : 1 or more, more preferably, 15 ~ 200 : 1. Furthermore, it is preferable that the electron donative organic compound be used in such an amount that the sum of the molar amounts of the electron donative organic compound and water contained in the second polymerization mixture be less than the molar amount of the dialkyl aluminium halide. Moreover, it is preferable that the content of the electron donative organic compound in the 1,2-polymerization catalyst be in the range of from 0.05 to 0.9 moles, more preferably, from 0.1 to 0.4 moles, per mole of the dialkyl aluminium halide.
The second polymerization procedure is preferably effected at a temperature of from -20 to 80C, more llS~84 preferably, from 20 to 60C, under atmospheric pressure or higher, for a period of from 10 minutes to 5 hours.
The polymerization medium to be contained in the second polymerization mixture may be the same as that in the first polymerization mixture.
In the process of the present invention, the first polymerization mixture may contain entire amounts of non-reacted 1,3-butadiene and the polymerization medium necessary for the production of the polybutadiene rubber.
In this case, after the first polymerization procedure is completed, the entire amount of the resultant first poly-merization mixture is used as a second polymerization mixture. In the other cases, the resultant first polymeri-zation mixture is admixed with an additional amount of the non-reacted 1,3-butadiene and/or the polymerization medium so as to prepare the second polymerization mixture containing the necessary amounts of the cis-1,4-polybutadiene, non--reacted 1,3-butadiene and polymerization medium. In any cases, it is preferable that the content of the non-reacted 1,3-butadiene in the second polymerization mixture be in the range of from 3 to 40% by weight.
In the industrial practice of the process of the present invention, each of the first and second polymeri-zations may be carried out in a batch-type procedure. In this case, after the first polymerization is completed, the second polymerization may be carried out in the same reaction vessel as that in which the first polymerization was conducted. Also, the first polymerization is carried out continuously and, then, the second polymerization is effected continuously by using a continuous polymerization reactor having a first polymerization zone and a successive second polymerization zone.
After the second polymerization procedure is completed, the resultant polybutadiene rubber can be isolated from the reaction mix~ure by a known method. For example, after the second polymerization reaction is completed, in order to stop the second polymerization, a large amount of a polar 115~
g solvent, for example, an alchol or water, which is reactive to the dialkyl aluminium halide is added to the reaction mixture to deactivate the 1,2-polymerization mixture. In another method, the reaction mixture is poured into a large amount of the polar solvent. In still another method, a small amount of a polar solvent containing an inorganic acid, for example, hydrochloric acid or sulfuric acid; an organic acid, for example, acetic acid or benzoic acid, or monoethanolamine or ammonia, to the resultant reaction mixture. In another method, hydrogen chloride gas is introduced into the reaction mixture. After the second polymerization is stopped, the resultant polybutadiene rubber is precipitated from the reaction mixture by adding a precipitating agent, for example, methyl alcohol or by evaporating the polymerization medium from the reaction mixture. The evaporation of the polymerization medium may be carried out by blowing steam into the reaction mixture.
The precipitated polymer is separated from the reaction mixture and, finally, dried.
In the process of the present invention, it is preferable that the amount of 1,3-butadiene cis-1,4--polymerized in the first polymerization procedure be in the range of 70 to 95% based on the entire weight of the polymerized 1,3-butadiene, and the amount of 1,3-butadiene 1,2-polymerized in the second polymerization procedure be in the range of from 5 to 30~ based on the entire weight ~f the polymerized 1,3-butadiene in this process.
The polybutadiene rubber prepared in accordance with the process of the present invention comprises a boiling 30 n-hexane-soluble fraction thereof having an intrinsic viscosity of from 1 to 5, determined in toluene at a temperature of 30C and containing 95% or more of a cis--1,4-structure and a boiling n-hexane-insoluble fraction thereof having a reduced viscosity of from 0.5 to 5, 35 determined in tetrahydronaphthalene at a temperature of 135C, and a melting point of 180C or more, and containing 85% or more of an 1,2-structure.
li5~84 In the polybutadiene rubber, it is preferable that the amount of the boiling n-hexane-soluble fraction be in the range of from 70 to 95% by weight and the amount of the boiling n-hexane-insoluble fraction be in the range of from 5 to 30% by weight.
The polybutadiene rubber obtained in accordance with the process of the present invention can be vulcanized by a known vulcanizing method, and the resultant vulcanized rubber product, for example, tire can exhibit an excellent tear strength, flex-crac~ resistance and tensile strength.
The polybutadiene rubber produced in accordance with the process of the present invention may contain conventional additives, for example, vulcanizing agent, vulcanizing accelerator, reinforcing agent, filler, antioxidant, pigment, process oil and the like, which are usually blended with natural rubber or high cis-1,4-polybutadiene rubbers.
Also, the polybutadiene rubber of the present invention may be blended with natural rubber or other synthetic rubbers.
The polybutadiene rubber produced in accordance with the present invention has not only the same advantaqe and feature as those of cis-1,4-polybutadiene, but also, has greatly enhanced tear strength and flex-crack resistance when the polybutadiene rubber is vulcanized and converted into a final product.
The present invention will be further explained in the following examples and through comparative examples. In the examples and the comparative examples, the amount of the boiling n-hexane-insoluble fraction of the resultant polybutadiene rubber was determined in such a manner that
2 g of the polybutadiene rubber was immersed in 200 mQ of n-hexane at a room temperature and extracted by using a Soxhet's extractor for 4 hours and, then, the non-extracted fraction was dried under vacuum. The weight of the dried fraction was measured. The amount of the boiling n-hexane--soluble fraction of the resultant polybutadiene rubber was determined is such a manner that the resultant solution llS~84 from the above-mentioned extraction procedure was subjected to a evaporation procedure in which the n-hexane is evapo-rated from the solution and, then, the residual fraction was dried under vacuum. The weight of the dried fraction was measured. The content of the boiling n-hexane-soluble fraction of the resultant polybutadiene rubber and the content of the cis-1,4-structure in the first polymeri-zation product were determined by means of an infrared absorption spectrum analysis (IR). The content of the 1,2-structure in the boiling n-hexane-insoluble fraction of the polybutadiene rubber was determined by means of a nuclear magnetic resonance spectrum (NMR). The melting point of the boiling n-hexane-insoluble fraction of the polybutadiene rubber was determined from a temperature at a peak point appearing in an endothermic curve of the poly-butadiene rubber measured by a recording differential scanning calorimeter (DSC).
The intrinsic viscosities rn] of the boiling n-hexane-soluble fraction of the polybutadiene rubber and the first polymerization product (cis-1,4-polymer) were determined in toluene at a temperature of 30C. Also, the reduced viscosity of the boiling n-hexane-insoluble fraction of the polybutadiene rubber was determined in tetrahydronaphthalene at a temperature of 135c.
Example 1 A solution of 74.8 g of dried 1,3-butadiene in 764 m~
of dehydrated benzene was placed in a two liter four neck separable flask with a thermometer, a stirrer and a conduit for introducing therein nitrogen gas, which flask was filled with nitrogen gas. The 1,3-butadiene solution contained 0.64 millimoles of water.
~ lhile maintaining the temperature of the 1,3-butadiene solution at a level of 30C, 4 millimoles of diethyl alu-minium chloride, 4.2 millimoles of COD and 0.017 millimoles of cobalt octoate were mixed with the 1,3-butadiene solution. The mixture was stirred at a temperature of 30~ for 30 minutes to subjected the 1,3-butadiene to a ~15088'?t cis-1,4-polymerization (the first polymerization procedure).
The resultant cis-1,4-polybutadiene exhibited an intrinsic viscosity of 2.90.
Just after the cis-1,4-polymerization was completed, 0.3 millimoles of carbon disulfide, 1.2 millimoles of acetone and 0.1 millimole of cobalt octoate were admixed with the resultant first polymerization mixture. The admixture was stirred at a temperature of 30C for 30 minutes so as to allow the non-reacted 1,3-butadiene in the admixture to 1,2-polymerize.
The resultant second reaction mixture was poured into a solution containing small amounts of 2,6-di-tert-butyl-4-methylphenol and hydrochloric acid in 1 liter of methyl alcohol, so as to stop the 1,2-polymerization and to allow the resultant rubber polymer to precipitate from the admixture. The rubber polymer was separated from the admixture, washed with methyl alcohol and, then, dried in a vacuum at a temperature of 50C.
The resultant polybutadiene rubber was obtained at a yeild of 59%.
The polybutadiene rubber contained 9.8% by weight of a boiling n-hexane-insoluble fraction thereof which exhibited a reduced viscosity of 1.56 and a melting point of 198C
and contained 90% or more of 1,2-structure, and the balance consisting of a boiling n-hexane-soluble fraction thereof which exhibited an intrinsic viscosity of 2.9 and contained 96% of cis-1,4-structure.
Example 2 The air in an one liter stainless steel autoclave equiped with a thermometer, a stirrer, a conduit for intro-ducing a catalyst and a conduit for blowing in nitrogen gas, was replaced with nitrogen gas. The autoclave was charged with a solution of 153 g of dried 1,3-butadiene in 553 mQ of dehydrated benzene. The solution contained 0.53 millimoles of water. The solution was mixed with 4.6 millimoles of diethyl aluminium chloride, 18.5 millimoles of COD and 0.02 millimoles of cobalt octoate. The mixture - ~L15~88'~
was stirred at a temperature of 40C for 30 minutes to allow the 1,3-butadiene to cis-1,4-polymerize. The resultant polymer had an intrinsic viscosity of 1.75.
Right after the completion of the cis-1,4-polymerization, the mixture was admixed with 0.3 millimoles of carbon disulfide, 1.3 millimoles of diethylene glycol di-n-butyl ether and 0.6 millimoles of cobalt octoate. The admixture was stirred at a temperature of 40C for 30 minutes so as to allow the non-polymerized 1,3-butadiene to 1,2-polymerize.
The 1,2-polymerization was stopped by the same method as that described in Example 1, and the resultant polybutadiene rubber was isolated in the same manner as that described in Example 1. The polybutadiene rubber was obtained at a yield of 66% and contained 13.3% by weight of a boiling n-hexane-insoluble fraction thereof which had a reduced viscosity of 1.85 and a melting point of 188C and contained 90~ or more of the 1,2-structure, and; the balance consist-ing of a boiling n-hexane-soluble fraction thereof which had an intrinsic viscosity of 1.75 and contained 97.6% of the cis-1,4-structure.
Example 3 The same procedures as those described in Example 2, were carried out, except that the diethylene glycol di-n--butyl ether was replaced by dimethyl fumarate. A poly-butadiene rubber was obtained at a yield of 62~ andcontained 12.5% of a boiling n-hexane-insoluble fraction _ thereof which had a melting point of 188C.
Example 4 The same procedures as those described in Example 2 were carried out, except that the diethylene glycol di-n--butyl ether was replaced by N,N-dimethyl formamide. The resultant polybutadiene rubber was obtained at a yield of 63% and contained 13.0~ of a boiling n-hexane-insoluble fraction thereof which had a melting point of 190C.
Example 5 The same procedures as those described in Example 2 were~ carried out, except that the diethylene-glycol ~151)88~
di-n-butyl ether was replaced by N,N-dimetlyl sulfoxide.
The resultant polybutadiene rubber was obtained at a yield of 59% and contained 11.5~ of a boiling n-hexane-insoluble fraction thereof which had a melting point of 191C.
Comparative Example 1 Procedures identical to those described in Example 1 were carried out, except that after the cis-1,4-polymeri-zation was completed, no acetone, carbon disulfide or cobalt octoate were admixed to the polymerization mixture, and the 1,2-polymerization was carried out at a temperature of 30C for 30 minutes.
As a result, a cis-1,4-polybutadiene was obtained at a yield of 68%. This cis-1,4-polybutadiene had an intrinsic viscosity of 2.75 and contained 1.2% of 1,2-structure, 0.7%
of trans-1,4-structure and 98.1% of cis-1,4-structure.
Example 6 A four neck separable flask having a capacity of 10 liters and equiped with a thermometer, a stirrer and a conduit for blowing-in nitrogen gas, was filled with the nitrogen gas and, then, charged with a solution of 425 g of dried 1,3-butadiene in 4300 mQ of dehydrated benzene. The solution contained 3.7 millimoles of water. The solution was mixed with 22.1 millimoles of diethyl aluminium chloride, 37.5 millimoles of COD, and 0.215 millimoles of cobalt octoate, while the temperature of the solution was--maintained at 35C. The mixture was stirred at the temper-ature of 35C for 40 minutes so as to cis-1,4-polymerize the l,3-butadiene. The resultant polymer exhibited an intrinsic viscosity of 1.70. The resultant polymer mixture was cooled to lSC and, then, admixed with 6.6 millimoles of diethylene glycol di-n-butyl ether, 250 g of 1,3--butadiene, 0.675 millimoles of cobalt octoate and, 1 millimole of carbon disulfide. The admixture was stirred at 15C for 30 minutes to 1,2-polymerize the 1,3-butadiene.
In order to stop the 1,2-polymerization, four liters of a methyl alcohol solution containing small amounts of - 115~38'~
2,6-di-tert-butyl-4-methylphenol and hydrochloric acid were added to the admixture. The resultant polybutadiene rubber was precipitated and separated from the admixture, washed with methyl alcohol and, finally, dried at a temperature of 50C in a vacuum.
The dried polybutadiene rubber was obtained at a yield of 56% and contained 11.9~ of a boiling n-hexane-insoluble fraction thereof having a reduced viscosity of 1.86 and a melting point of 198C and containing 90% or more of the 1,2-structure and; the balance consisting of a boiling n-hexane-soluble fraction thereof having an intrinsic viscosity of 1.7 and containing 96.6% of the cis-1,4--structure.
The polybutadiene rubber was converted into a composition as indicated below.
Component Pmount (part by weight) Polybutadiene rubber 100 HAF Carbon( ) 50 Naphthene type press oil 10 Zinc oxide 5 Stearic acid 2 Amine type autioxidant 1 1 -Cyclohexyl-benzothiazyl ~lphenamide 1 Sulphur 1.5 Note: Oil absorption: 80 g Fer 100 g of the car~on Surface area : 85 m2 per g of the carbon particles The composition was uniformly mixed by using a Brabender plastograph having a capacity of 60 m~ and, then, by using a roll mixer, and vulcanized at a temperature of ~15(~884 140C for 30 minutes. The vulcanizing procedure was applied to a portion of the composition which was subjected to the measurement of a flex-crack resistance of the vulcanized composition, at 140C for 75 minutes. The properties of 5 the vulcanized composition was determined in accordance with Japanese Industrial Standard K-6301. For the purpose of comparison, the same procedures as those mentioned above were carried out, except that the polybutadiene rubber was replaced by a commercially available high cis-1,4-poly-10 butadiene.
The properties of the vulcanized composition of thepresent example and the comparative vulcanized composition are indicated in Table 1.
Table 1 ItemThe present C~nparative exampleccn~position Hardners 72 56 300% modulus (kg/cm ) 129 72 Ultimate elongation (%) 420 570 Tensile strength (kg/cm2) 170 175 Tear strength (kg/cm2)(*)160 33 Impact resilienoe (%) 57 65 Flex-crack resistance (*)2> 200,0001,600 Note: (*)l ... The tear strength was measured in accordance with B-type test method described in JIS K-6301.
(*)2 The flex-crack resistance was repre-35 sented by the number of flexing operations at which thelength of a crack created in a testing specimen reached from 2 mm to 15 mm.
-
The intrinsic viscosities rn] of the boiling n-hexane-soluble fraction of the polybutadiene rubber and the first polymerization product (cis-1,4-polymer) were determined in toluene at a temperature of 30C. Also, the reduced viscosity of the boiling n-hexane-insoluble fraction of the polybutadiene rubber was determined in tetrahydronaphthalene at a temperature of 135c.
Example 1 A solution of 74.8 g of dried 1,3-butadiene in 764 m~
of dehydrated benzene was placed in a two liter four neck separable flask with a thermometer, a stirrer and a conduit for introducing therein nitrogen gas, which flask was filled with nitrogen gas. The 1,3-butadiene solution contained 0.64 millimoles of water.
~ lhile maintaining the temperature of the 1,3-butadiene solution at a level of 30C, 4 millimoles of diethyl alu-minium chloride, 4.2 millimoles of COD and 0.017 millimoles of cobalt octoate were mixed with the 1,3-butadiene solution. The mixture was stirred at a temperature of 30~ for 30 minutes to subjected the 1,3-butadiene to a ~15088'?t cis-1,4-polymerization (the first polymerization procedure).
The resultant cis-1,4-polybutadiene exhibited an intrinsic viscosity of 2.90.
Just after the cis-1,4-polymerization was completed, 0.3 millimoles of carbon disulfide, 1.2 millimoles of acetone and 0.1 millimole of cobalt octoate were admixed with the resultant first polymerization mixture. The admixture was stirred at a temperature of 30C for 30 minutes so as to allow the non-reacted 1,3-butadiene in the admixture to 1,2-polymerize.
The resultant second reaction mixture was poured into a solution containing small amounts of 2,6-di-tert-butyl-4-methylphenol and hydrochloric acid in 1 liter of methyl alcohol, so as to stop the 1,2-polymerization and to allow the resultant rubber polymer to precipitate from the admixture. The rubber polymer was separated from the admixture, washed with methyl alcohol and, then, dried in a vacuum at a temperature of 50C.
The resultant polybutadiene rubber was obtained at a yeild of 59%.
The polybutadiene rubber contained 9.8% by weight of a boiling n-hexane-insoluble fraction thereof which exhibited a reduced viscosity of 1.56 and a melting point of 198C
and contained 90% or more of 1,2-structure, and the balance consisting of a boiling n-hexane-soluble fraction thereof which exhibited an intrinsic viscosity of 2.9 and contained 96% of cis-1,4-structure.
Example 2 The air in an one liter stainless steel autoclave equiped with a thermometer, a stirrer, a conduit for intro-ducing a catalyst and a conduit for blowing in nitrogen gas, was replaced with nitrogen gas. The autoclave was charged with a solution of 153 g of dried 1,3-butadiene in 553 mQ of dehydrated benzene. The solution contained 0.53 millimoles of water. The solution was mixed with 4.6 millimoles of diethyl aluminium chloride, 18.5 millimoles of COD and 0.02 millimoles of cobalt octoate. The mixture - ~L15~88'~
was stirred at a temperature of 40C for 30 minutes to allow the 1,3-butadiene to cis-1,4-polymerize. The resultant polymer had an intrinsic viscosity of 1.75.
Right after the completion of the cis-1,4-polymerization, the mixture was admixed with 0.3 millimoles of carbon disulfide, 1.3 millimoles of diethylene glycol di-n-butyl ether and 0.6 millimoles of cobalt octoate. The admixture was stirred at a temperature of 40C for 30 minutes so as to allow the non-polymerized 1,3-butadiene to 1,2-polymerize.
The 1,2-polymerization was stopped by the same method as that described in Example 1, and the resultant polybutadiene rubber was isolated in the same manner as that described in Example 1. The polybutadiene rubber was obtained at a yield of 66% and contained 13.3% by weight of a boiling n-hexane-insoluble fraction thereof which had a reduced viscosity of 1.85 and a melting point of 188C and contained 90~ or more of the 1,2-structure, and; the balance consist-ing of a boiling n-hexane-soluble fraction thereof which had an intrinsic viscosity of 1.75 and contained 97.6% of the cis-1,4-structure.
Example 3 The same procedures as those described in Example 2, were carried out, except that the diethylene glycol di-n--butyl ether was replaced by dimethyl fumarate. A poly-butadiene rubber was obtained at a yield of 62~ andcontained 12.5% of a boiling n-hexane-insoluble fraction _ thereof which had a melting point of 188C.
Example 4 The same procedures as those described in Example 2 were carried out, except that the diethylene glycol di-n--butyl ether was replaced by N,N-dimethyl formamide. The resultant polybutadiene rubber was obtained at a yield of 63% and contained 13.0~ of a boiling n-hexane-insoluble fraction thereof which had a melting point of 190C.
Example 5 The same procedures as those described in Example 2 were~ carried out, except that the diethylene-glycol ~151)88~
di-n-butyl ether was replaced by N,N-dimetlyl sulfoxide.
The resultant polybutadiene rubber was obtained at a yield of 59% and contained 11.5~ of a boiling n-hexane-insoluble fraction thereof which had a melting point of 191C.
Comparative Example 1 Procedures identical to those described in Example 1 were carried out, except that after the cis-1,4-polymeri-zation was completed, no acetone, carbon disulfide or cobalt octoate were admixed to the polymerization mixture, and the 1,2-polymerization was carried out at a temperature of 30C for 30 minutes.
As a result, a cis-1,4-polybutadiene was obtained at a yield of 68%. This cis-1,4-polybutadiene had an intrinsic viscosity of 2.75 and contained 1.2% of 1,2-structure, 0.7%
of trans-1,4-structure and 98.1% of cis-1,4-structure.
Example 6 A four neck separable flask having a capacity of 10 liters and equiped with a thermometer, a stirrer and a conduit for blowing-in nitrogen gas, was filled with the nitrogen gas and, then, charged with a solution of 425 g of dried 1,3-butadiene in 4300 mQ of dehydrated benzene. The solution contained 3.7 millimoles of water. The solution was mixed with 22.1 millimoles of diethyl aluminium chloride, 37.5 millimoles of COD, and 0.215 millimoles of cobalt octoate, while the temperature of the solution was--maintained at 35C. The mixture was stirred at the temper-ature of 35C for 40 minutes so as to cis-1,4-polymerize the l,3-butadiene. The resultant polymer exhibited an intrinsic viscosity of 1.70. The resultant polymer mixture was cooled to lSC and, then, admixed with 6.6 millimoles of diethylene glycol di-n-butyl ether, 250 g of 1,3--butadiene, 0.675 millimoles of cobalt octoate and, 1 millimole of carbon disulfide. The admixture was stirred at 15C for 30 minutes to 1,2-polymerize the 1,3-butadiene.
In order to stop the 1,2-polymerization, four liters of a methyl alcohol solution containing small amounts of - 115~38'~
2,6-di-tert-butyl-4-methylphenol and hydrochloric acid were added to the admixture. The resultant polybutadiene rubber was precipitated and separated from the admixture, washed with methyl alcohol and, finally, dried at a temperature of 50C in a vacuum.
The dried polybutadiene rubber was obtained at a yield of 56% and contained 11.9~ of a boiling n-hexane-insoluble fraction thereof having a reduced viscosity of 1.86 and a melting point of 198C and containing 90% or more of the 1,2-structure and; the balance consisting of a boiling n-hexane-soluble fraction thereof having an intrinsic viscosity of 1.7 and containing 96.6% of the cis-1,4--structure.
The polybutadiene rubber was converted into a composition as indicated below.
Component Pmount (part by weight) Polybutadiene rubber 100 HAF Carbon( ) 50 Naphthene type press oil 10 Zinc oxide 5 Stearic acid 2 Amine type autioxidant 1 1 -Cyclohexyl-benzothiazyl ~lphenamide 1 Sulphur 1.5 Note: Oil absorption: 80 g Fer 100 g of the car~on Surface area : 85 m2 per g of the carbon particles The composition was uniformly mixed by using a Brabender plastograph having a capacity of 60 m~ and, then, by using a roll mixer, and vulcanized at a temperature of ~15(~884 140C for 30 minutes. The vulcanizing procedure was applied to a portion of the composition which was subjected to the measurement of a flex-crack resistance of the vulcanized composition, at 140C for 75 minutes. The properties of 5 the vulcanized composition was determined in accordance with Japanese Industrial Standard K-6301. For the purpose of comparison, the same procedures as those mentioned above were carried out, except that the polybutadiene rubber was replaced by a commercially available high cis-1,4-poly-10 butadiene.
The properties of the vulcanized composition of thepresent example and the comparative vulcanized composition are indicated in Table 1.
Table 1 ItemThe present C~nparative exampleccn~position Hardners 72 56 300% modulus (kg/cm ) 129 72 Ultimate elongation (%) 420 570 Tensile strength (kg/cm2) 170 175 Tear strength (kg/cm2)(*)160 33 Impact resilienoe (%) 57 65 Flex-crack resistance (*)2> 200,0001,600 Note: (*)l ... The tear strength was measured in accordance with B-type test method described in JIS K-6301.
(*)2 The flex-crack resistance was repre-35 sented by the number of flexing operations at which thelength of a crack created in a testing specimen reached from 2 mm to 15 mm.
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Claims (18)
1. A process for producing a polybutadiene rubber with an enhanced mechanical strength, comprising the two successive steps of:
(A) subjecting a first polymerization mixture comprising 1,3-butadiene and a polymerization medium to a first polymerization in the presence of a cis-1,4-polymerization catalyst which comprises (a) a cobalt compound soluble in said polymerization medium, and (b) a dialkyl aluminium halide of the formula (I):
A?R2X (I) wherein R represents an alkyl radical having 2 to 8 carbon atoms and X represents a halogen atom, to convert at least a portion of the amount of said 1,3-butadiene used to a cis-1,4-polybutadiene, and;
(B) subjecting a second polymerization mixture comprising the resultant cis-1,4-polybutadiene, non-reacted 1,3-butadiene and said polymerization medium, to a second polymerization in the presence of a 1,2-polymerization catalyst which comprises (c) from 0.005 to 0.5 millimoles of a cobalt compound soluble in said polymerization medium, said cobalt compound being selected from cobalt com-plexes with .beta.-diketones of the formula (II):
(II) wherein R1 and R2 represent an aliphatic hydrocarbon radical having 1 to 3 carbon atoms, respectively, and R3 and R4 represent at least one member selected from the group consisting of a hydrogen atom and aliphatic hydrocarbon radicals having 1 to 3 carbon atoms, re-spectively; cobalt complexes with .beta.-keto acid esters of the formula (III):
(III) wherein R1, R2, R3 and R4 are as defined in the pre-ceding formula (II); cobalt salts of organic carboxylic acids having 6 or more carbon atoms and; cobalt halide complexes of the formula (IV):
CoXnYm (IV) wherein X represents a halogen atom,n represents an integer of 2 or 3, Y represents an organic ligand capa-ble of forming a complex in coordination with the cobalt halide and m represents an integer of from 1 to 4, (d) from 0.1 to 50 millimoles of a dialkyl aluminium halide of said formula (I), (e) from 0.01 to 10 millimoles of carbon disulfide, and (f) from 0.05 to 5 millimoles of an electron donative organic compound, to convert said cis-1,4-polybutadiene and said 1,3-butadiene to a poly-butadiene rubber, said electron donative organic compound being selected from aliphatic polyethers, ali-phatic carboxylic esters, aliphatic ketones, aliphatic acetals, aliphatic N,N-dialkyl amides, aliphatic dialkyl sulfoxides and trialkyl phosphates.
(A) subjecting a first polymerization mixture comprising 1,3-butadiene and a polymerization medium to a first polymerization in the presence of a cis-1,4-polymerization catalyst which comprises (a) a cobalt compound soluble in said polymerization medium, and (b) a dialkyl aluminium halide of the formula (I):
A?R2X (I) wherein R represents an alkyl radical having 2 to 8 carbon atoms and X represents a halogen atom, to convert at least a portion of the amount of said 1,3-butadiene used to a cis-1,4-polybutadiene, and;
(B) subjecting a second polymerization mixture comprising the resultant cis-1,4-polybutadiene, non-reacted 1,3-butadiene and said polymerization medium, to a second polymerization in the presence of a 1,2-polymerization catalyst which comprises (c) from 0.005 to 0.5 millimoles of a cobalt compound soluble in said polymerization medium, said cobalt compound being selected from cobalt com-plexes with .beta.-diketones of the formula (II):
(II) wherein R1 and R2 represent an aliphatic hydrocarbon radical having 1 to 3 carbon atoms, respectively, and R3 and R4 represent at least one member selected from the group consisting of a hydrogen atom and aliphatic hydrocarbon radicals having 1 to 3 carbon atoms, re-spectively; cobalt complexes with .beta.-keto acid esters of the formula (III):
(III) wherein R1, R2, R3 and R4 are as defined in the pre-ceding formula (II); cobalt salts of organic carboxylic acids having 6 or more carbon atoms and; cobalt halide complexes of the formula (IV):
CoXnYm (IV) wherein X represents a halogen atom,n represents an integer of 2 or 3, Y represents an organic ligand capa-ble of forming a complex in coordination with the cobalt halide and m represents an integer of from 1 to 4, (d) from 0.1 to 50 millimoles of a dialkyl aluminium halide of said formula (I), (e) from 0.01 to 10 millimoles of carbon disulfide, and (f) from 0.05 to 5 millimoles of an electron donative organic compound, to convert said cis-1,4-polybutadiene and said 1,3-butadiene to a poly-butadiene rubber, said electron donative organic compound being selected from aliphatic polyethers, ali-phatic carboxylic esters, aliphatic ketones, aliphatic acetals, aliphatic N,N-dialkyl amides, aliphatic dialkyl sulfoxides and trialkyl phosphates.
2. A process as claimed in Claim 1, wherein said dialkyl aluminium halide of the formula (I) is diethyl aluminium chloride.
3. A process as claimed in Claim 1, wherein said cis-1,4- polymerization catalyst used contains 0.005 millimoles or more of said cobalt compound and 0.5 millimoles or more of said dialkyl aluminium halide per mole of said 1,3-butadiene contained in said first polymerization mixture.
4. A process as claimed in Claim 1, wherein the molar ratio of the amount of said dialkyl aluminium halide to the amount of said cobalt compound in said cis-1,4-polymerization catalyst is 5 : 1 or more.
5. A process as claimed in Claim 1, wherein said polymerization medium is an organic solvent capable of dissolving said cis-1,4-polybutadiene.
6. A process as claimed in Claim 5, wherein said polymerization medium contains 5 to 50 mg/? of water.
7. A process as claimed in Claim 1, wherein said first polymerization is carried out at a tempera-ture of from -20 to 80°C.
8. A process as claimed in Claim 1, wherein the content of 1,3-butadiene in said first polymeri-zation mixture is in the range of from 5 to 40% based on the entire weight of the first polymerization mixture.
9. A process as claimed in Claim 1, wherein the resultant cis-1,4-polybutadiene contains 90% or more of cis-1,4-structure, and has an intrinsic viscosity of from 1 to 4, determined in toluene at a temperature of 30°C.
10. A process as claimed in Claim 1, wherein said carbon disulfide contains substantially no water.
11. A process as claimed in Claim 1, where in said 1,2-polymerization catalyst, the molar ratio of the amount of said dialkyl aluminium halide to the amount of said cobalt compound is 5 : 1 or more.
12. A process as claimed in Claim 1, wherein the sum of the molar amounts of said electron donative organic compound and water contained in said second polymerization mixture is less than the molar amount of said dialkyl aluminium halide.
13. A process as claimed in Claim 1, wherein said second polymerization is carried out at a tempera-ture of from -20 to 80°C.
14. A process as claimed in Claim 1, wherein the content of the non-reacted 1,3-butadiene in said second polymerization mixture is in the range of from 3 to 40% by weight.
15. A process as claimed in Claim 1, wherein the amount of 1,3-butadiene cis-1,4-polymerized in said first polymerization is in the range of 70 to 95% based on the entire weight of the polymerized 1,3-butadiene in this process.
16. A process as claimed in Claim 1, wherein the amount of 1,3-butadiene 1,2-polymerized in said second polymerization is in the range of 5 to 30% based on the entire weight of the polymerized 1,3-butadiene in this process.
17. A polybutadiene rubber produced in accord-ance with the process as claimed in Claim 1, which comprises a boiling n-hexane-soluble fraction thereof having an intrinsic viscosity of from 1 to 5 determined in toluene at a temperature of 30°C and containing 95%
or more of a cis-1,4-structure, and a boiling n-hexane-insoluble fraction having a reduced viscosity of from 0.5 to 5, determined in tetrahydronaphthalene at a temperature of 135°C, and a melting point of 180°C or more, and containing 85% or more of an 1,2-structure.
or more of a cis-1,4-structure, and a boiling n-hexane-insoluble fraction having a reduced viscosity of from 0.5 to 5, determined in tetrahydronaphthalene at a temperature of 135°C, and a melting point of 180°C or more, and containing 85% or more of an 1,2-structure.
18. A polybutadiene rubber as claimed in Claim 17, wherein the amount of said boiling n-hexane-soluble fraction is in the range of from 70 to 95% by weight and the amount of said boiling n-hexane-insoluble fraction is in the range of from 5 to 30% by weight.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16477379A JPS5688409A (en) | 1979-12-20 | 1979-12-20 | Preparation of reinforced polybutadiene rubber |
| JP164773/79 | 1979-12-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1150884A true CA1150884A (en) | 1983-07-26 |
Family
ID=15799656
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000366910A Expired CA1150884A (en) | 1979-12-20 | 1980-12-16 | Process for producing polybutadiene rubber with enhanced mechanical strength |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4379889A (en) |
| EP (1) | EP0034235B1 (en) |
| JP (1) | JPS5688409A (en) |
| CA (1) | CA1150884A (en) |
| DE (1) | DE3067394D1 (en) |
Families Citing this family (27)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5834816A (en) * | 1981-08-27 | 1983-03-01 | Ube Ind Ltd | Production of 1,2-polybutadiene |
| JPS58109513A (en) * | 1981-12-24 | 1983-06-29 | Ube Ind Ltd | Production of reinforced polybutadiene rubber |
| JPS5968316A (en) * | 1982-10-14 | 1984-04-18 | Ube Ind Ltd | Polymerization of 1,3-butadiene |
| JPS60161408A (en) * | 1984-02-01 | 1985-08-23 | Japan Synthetic Rubber Co Ltd | Preparation of diene polymer |
| JP3463811B2 (en) * | 1991-04-24 | 2003-11-05 | Ｊｓｒ株式会社 | Method for producing butadiene-based polymer |
| US6117956A (en) * | 1998-06-01 | 2000-09-12 | Bridgestone Corporation | Catalyst composition and polymerization process for producing syndiotactic 1,2-polybutadiene |
| US6211313B1 (en) | 1999-11-12 | 2001-04-03 | Bridgestone Corporation | Iron-based catalyst composition and process for producing conjugated diene polymers |
| US6399732B2 (en) | 1998-10-14 | 2002-06-04 | Bridgestone Corporation | Preparation of conjugated diene polymers by using an iron-based catalayst system |
| US6281305B1 (en) | 1999-11-05 | 2001-08-28 | Bridgestone Corporation | Iron-based catalyst for producing oligomers of conjugated dienes |
| US6197888B1 (en) | 1999-12-30 | 2001-03-06 | Bridgestone Corporation | Process for producing blends of syndiotactic 1, 2-polybutadiene and rubbery elastomers with an iron-based catalyst system |
| US6288183B1 (en) | 1999-12-30 | 2001-09-11 | Bridgestone Corporation | Catalyst composition and process for controlling the characteristics of conjugated diene polymers |
| EP1252211B1 (en) * | 1999-12-30 | 2013-07-24 | Bridgestone Corporation | Copolymers prepared by using both anionic polymerization techniques and coordination catalysts |
| US6765066B2 (en) | 1999-12-30 | 2004-07-20 | Bridgestone Corporation | Copolymers prepared by using both anionic polymerization techniques and coordination catalysts |
| US6160063A (en) * | 1999-12-30 | 2000-12-12 | Bridgestone Corporation | Iron-based catalyst for producing binary cis-1,4-/1,2-polybutadiene |
| US6303692B1 (en) | 2000-04-13 | 2001-10-16 | Bridgestone Corporation | Preparation of blends of syndiotactic 1,2-polybutadiene and rubbery elastomers with a molybdenum-based catalyst system |
| WO2001079309A2 (en) | 2000-04-13 | 2001-10-25 | Bridgestone Corporation | USE OF A Cr- OR Mo-BASED CATALYST SYSTEM TO PRODUCE BLENDS OF SYNDIOTACTIC 1,2-POLYBUTADIENE AND RUBBERY ELASTOMERS |
| US6291591B1 (en) | 2000-04-13 | 2001-09-18 | Bridgestone Corporation | Process for producing blends of syndiotactic 1,2-polybutadiene and rubbery elastomers with a chromium-based catalyst system |
| US6348550B1 (en) | 2000-04-13 | 2002-02-19 | Bridgestone Corporation | Molybdenum-based catalyst composition and process for controlling the characteristics of conjugated diene polymers |
| US6627712B2 (en) | 2001-02-19 | 2003-09-30 | Bridgestone Corporation | Manufacture of conjugated diene polymers by using an iron-based catalyst composition |
| US6320004B1 (en) | 2001-04-05 | 2001-11-20 | Bridgestone Corporation | Manufacture of conjugated diene polymers by using an iron-based catalyst composition |
| US6545107B2 (en) | 2001-06-08 | 2003-04-08 | Bridgestone Corporation | Molydenum-based catalyst composition for producing syndiotactic 1,2-polybutadiene |
| TWM240688U (en) * | 2003-07-16 | 2004-08-11 | Molex Taiwan Ltd | Conductive terminal |
| TWI386419B (en) * | 2004-12-20 | 2013-02-21 | Ube Industries | Process for producing polybutadiene rubber and rubber composition |
| BRPI0519513A2 (en) * | 2004-12-21 | 2009-02-25 | Ube Industries | rubber makeup |
| US10035908B1 (en) | 2013-12-03 | 2018-07-31 | Bridgestone Corporation | Process for preparing blends of trans-1,4-polybutadiene and syndiotactic 1,2-polybutadiene |
| JP6631923B2 (en) | 2013-12-03 | 2020-01-15 | 株式会社ブリヂストン | Process for preparing a blend of cis-1,4-polybutadiene and syndiotactic 1,2-polybutadiene |
| CN114426610B (en) * | 2020-10-29 | 2024-05-31 | 中国石油化工股份有限公司 | Method for adjusting scorch time and positive vulcanization time of butadiene rubber |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL132382C (en) * | 1959-11-18 | |||
| US3522332A (en) * | 1967-06-02 | 1970-07-28 | Japan Synthetic Rubber Co Ltd | Process for the preparation of 1,2-polybutadiene |
| GB1372399A (en) * | 1970-12-25 | 1974-10-30 | Ube Industries | Process for producing polybutadiene |
| US3935180A (en) * | 1971-12-21 | 1976-01-27 | Ube Industries, Ltd. | Polybutadiene and process for producing same |
| US3993856A (en) * | 1974-07-25 | 1976-11-23 | The Firestone Tire & Rubber Company | Process for polymerizing butadiene |
| US4258160A (en) * | 1977-12-22 | 1981-03-24 | The Firestone Tire & Rubber Company | Process for polymerizing butadiene |
| JPS56109204A (en) * | 1980-01-31 | 1981-08-29 | Japan Synthetic Rubber Co Ltd | Preparation of polybutadiene |
-
1979
- 1979-12-20 JP JP16477379A patent/JPS5688409A/en active Granted
-
1980
- 1980-12-16 CA CA000366910A patent/CA1150884A/en not_active Expired
- 1980-12-16 US US06/216,869 patent/US4379889A/en not_active Expired - Lifetime
- 1980-12-17 DE DE8080304574T patent/DE3067394D1/en not_active Expired
- 1980-12-17 EP EP80304574A patent/EP0034235B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5688409A (en) | 1981-07-17 |
| DE3067394D1 (en) | 1984-05-10 |
| EP0034235B1 (en) | 1984-04-04 |
| JPS6138724B2 (en) | 1986-08-30 |
| US4379889A (en) | 1983-04-12 |
| EP0034235A1 (en) | 1981-08-26 |
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